Disentangling neuroimmune landscapes during divergent peripheral activation states reveals distinct glial signatures

Disentangling neuroimmune landscapes across peripheral activation paradigms resolves divergent glial state programs | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Disentangling neuroimmune landscapes across peripheral activation paradigms resolves divergent glial state programs Mahesh Chandra Kodali, Zhengjun Wang, Geng Lin, Francesca-Fang Liao This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8844780/v2 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 2 posted 12 You are reading this latest preprint version Show more versions Abstract Lipopolysaccharide (LPS), a gram-negative bacterial cell-wall component, is a well-characterized immunostimulant acting via Toll-like receptor 4 (TLR4) and is widely used to model systemic inflammation–to–brain immune signaling. A single intraperitoneal high dose evokes a robust peripheral inflammatory state that is rapidly relayed to the central nervous system (CNS), resulting in profound neuroinflammation. By contrast, repeated low-dose LPS engages innate immune memory and has been associated with neuroprotective effects. Here we sought to comprehensively characterize the CNS-specific effects of the repeated LPS regimen relative to a neurotoxic single high-dose challenge. High-dose LPS induced robust forebrain inflammatory cytokine expression, disrupted homeostatic microglial and astrocytic marker programs, and produced transcriptomic signatures enriched for NF-κB signaling and apoptosis. In striking contrast, repeated low-dose LPS preserved homeostatic glial marker expression while increasing IBA1/F4/80-positive microglial signal across forebrain regions without a parallel increase in inflammatory cytokine transcripts, demonstrating a dissociation between gliosis marker intensity and inflammatory pathway activation. Whole-forebrain RNA-seq demonstrated selective enrichment of phagocytosis-related pathways under the repeated regimen in the absence of pro-inflammatory transcriptional amplification. Flow cytometry revealed an expansion of CD45 high CD11b + myeloid cells expressing the phagocytic marker CD206 following repeated low-dose LPS. Cell-type–resolved transcriptional profiling showed that this CD45 high CD11b + subset preferentially upregulated phagocytic programs while lacking prominent pro-inflammatory and apoptotic pathway activation. In parallel, astrocytes maintained homeostatic gene expression without enrichment of neurotoxic inflammatory signatures. Together, these findings delineate how distinct systemic LPS dosing paradigms differentially shape glial transcriptional and phenotypic responses in the CNS. Microglia Repeated Low Dose LPS Neuroinflammation Lipopolysaccharide CNS myeloid cells Full Text Additional Declarations No competing interests reported. Supplementary Files Supplementaryfigures01292026.pdf SupplementaryFigurelegends02102026.pdf Cite Share Download PDF Status: Under Revision Version 2 posted Editorial decision: Revision requested 01 Apr, 2026 Reviews received at journal 27 Mar, 2026 Reviews received at journal 27 Mar, 2026 Reviews received at journal 15 Mar, 2026 Reviewers agreed at journal 09 Mar, 2026 Reviewers agreed at journal 08 Mar, 2026 Reviewers agreed at journal 07 Mar, 2026 Reviewers agreed at journal 07 Mar, 2026 Reviewers invited by journal 07 Mar, 2026 Editor assigned by journal 07 Mar, 2026 Submission checks completed at journal 06 Mar, 2026 First submitted to journal 01 Mar, 2026 You are reading this latest preprint version Show more versions Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8844780","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[{"code":1,"date":"2026-02-19 04:34:59","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research 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